Luminescent-tube lamp



Sept. 16, 1930. s. c. MILLER I LUMINESCENT TUBE LAMP Filed Oct.31, 1928 v Patented Sept. 16, 1930 UNITED STATES.

PATENT- OFFICE SAMUEL C; MILLER, OF NEW YORK, N. Y.

LUMINESCENT-TUIBE LAMP Application filed October 31, 1928. Serial No. 316,277.

The subject matter of the present invention relates to an improved form of lamp adapted to be connected to the'opposite ends of a luminous tube used for light purposes,

such as luminescent display signs, said tube forming a long discharge path between the opposed electrodes sealed within the lamps,

and adapted to contain an inert gas, such as neon, helium, argon, or thelike,which serves as the conducting medium of an electrical current.

Heretofore it has, been the practice to employ a single electrode having an area exceeding 1.5 square decimeters per ampere, this 16 relatively large area being thought necessary in order to decrease the vaporization of said electrodes and to further prevent the formationof metallic deposits upon the walls of the lamp, contiguous to said electrodes, such 20 deposits materially contributing to the deterioration of the latter, and further having theefiect of trapping the contained gas and in consequence limiting the life of .the lamp;

As will presently appear, my invention erably presenting coiled inner ends arranged together and extending outside the lamp for connection with a conduit to receive electric current from a suitable source.

Accordingly, the primary object of the inminimum by the simple expedient of disl 'tributing the contained voltage among the several elements comprising the electrode 40 and hence materially decreasing the electronic bombardment per electrode.

Another object resides in the provision of an electrode of the above-mentioned character, wherein the combined area of the plurality of elements composing the same is less than 1.5 square 'decimetersper ampereof- -current. Y r

A further object of the invention is to provide means .for preventing the formation of line 3-3 of Fig. 2.

contemplates the provision of alamp havinga plurality of elements sealed therein,said elements comprising the electrodeand pref in spaced parallel relation within said lamp, the outer ends of said elementsbeing coupled vention is to provide'a novel form of lamp wherein deterioration may be reduced to a a metallic deposit within the lamp by lessen-- ing and counteracting the electronic bombardaccompanying drawing, wherein:

Figure is an elevation of said lamp;. I Fig. 2 1s a central"longi tudinal sectional v1ewthereoflshowing the j electrode in elevation; and

Fig. 3 is atransverse section taken on the Referring now in particular] to thepreferredillust'ration of the inyention, let 5 denote. a'l'am'p constructed infaccordanc'e with my lHVQIltIQI I, the same comprising a bulbous member'adapted to be connected to one "end 7.

of a luminescent tube'6 of a display ,sign or the likel,"containing an inert gas, such'as neon, "hellum or argon. It is proposed to arrange Saidtube 6 in accordance with the design to be dlsplayedrand'to provide alamp'atach of z-sc its ends, each lam'p containing an electrode.

and the electrodes serving for the passage of an electric current that flows through'the gas in'said-tube thereby producing a luminous effect. 35

As shown in Fig. 2 the. electrode? comprises-a plurality of elements, preferably constructed from tungsten wire, extending longitudinally of the lamp and maintainedin spaced parallel relation by embedment in the an insulating bushing 8, the embedded ends being connected to conductors 9, serving to couple the elements of the electrode to a single conduit 10 leading from a suitable. source of electriccurrent. 'The inwardly directed recessed extension 11 and the insulating bushing 8 seal'that particular end of the lamp and may be provided with a filling or plug means if desired. The inner po'rtions of the elec- I trodeelements 7 are spaced apart, their 109 tremities each carryinga coil 12, which coils are also arranged in spaced parallelism with res set to each other.

rom the foregoing it is apparent that my novel lamp comprises a plurality of electrode elements, each separated from the others, and in view of this arrangement the voltage within the lamp is distributed among said electrode elements and hence the electronic bombardment per electrode element is small and is less for the group of elements than if they were concentrated as a single unit. De-

terioration is therefore reduced to a minimum, whichis a feature of considerable importance, and further the arrangement is such that the combined area of the electrode elements does not exceed 1.5 square decimeters per ampere. The formation of the elecv trodes from tungsten wire prevents disintegration thereof when the luminescent tube is given an internal bombardment during the pumping process.

In order to prevent the formation of a metallic deposit within the lamp, I provide each lamp with a metallic shield 13, said shield preferably embracing the external portion of said lamp and being positioned adj acent the electrode 7, said shield being connected to the conduit 10 by means of a connector 14. This shield prevents .the disintegration of the electrode and the accumulation of the aforesaid deposit by causing an electrostatic field to be formed around the electrode, tending to counteract the terrific electronic bombardment which it-would otherwise be subjected to.

It will,,of course, be understood'that it is 4 within the province of my invention to sub-' stitute for said metallic shield a metallic coating'adjaoent said electrode and further the connector 14,may be dispensed with by directly extending said metallic shield to a;

plug attached tothe outer end of each base or IaIpTp. v ariations'within the spirit and scope of myinventionare equally comprehended by y the foregoing disclosure.

I claim: I In a lamp of the luminescent tube type, the

combination comprising a bulbous member,-

a plurality of electrodes positioned in spaced parallel relation within said bulbous member, an electrical conduit connected to said electrodes and a metallic shield surrounding said electrodes and said bulbous \member and joined to said conduit and adapted to counter 7 act the electronic bombardment of said electrodes. A

-Signed at New' York, in theicity, county and State of, New York, this 17th day of October, 1928.

SAMUEL C. MILLER. 

